From: Mark Powell <medp@primagraphics.co.uk>
To: cwernham@airspan.com
Cc: linuxppc-dev@ozlabs.org
Subject: Re: PPC4XX DMA polarity bug in linuxppc-2.6.9
Date: Mon, 13 Dec 2004 09:48:47 +0000 [thread overview]
Message-ID: <41BD657F.7010000@primagraphics.co.uk> (raw)
In-Reply-To: <41B8255A.3040101@airspan.com>
Colin Wernham wrote:
> I believe that there is a PPC4xx DMA driver bug in the following
> kernel, file and function:
> linuxppc-2.6.9,
> /arch/ppc/syslib/ppc4xx_dma.c,
> ppc4xx_init_dma_channel()
>
>
> Is there anyone else using the PPC4XX DMA?
FWIW
I have used the PPC4xx dma on 405GP systems and a 440GP system with
2.4.21 and 2.4.25. I found the ppc4xx_dma.c functions didn't work in the
way I needed. I just read the code very carefully and used a few of the
functions combined with some direct manipulation of the DMA registers.
As I recall, I don't think the polarity is the only problem in that
file. It certainly doesn't support the 440 DMA registers - the COUNT
register is different.
The code in ppc4xx_dma.c is however, very useful as a guide in how to go
about setting up a DMA transfer; just read it carefully with the
processor manual to hand.
--
Mark Powell, Senior Software Engineer
Curtiss-Wright Controls Embedded Computing
Tel: +44 (0) 1763 852222
Email: medp@primagraphics.com
next prev parent reply other threads:[~2004-12-13 9:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-09 10:13 PPC4XX DMA polarity bug in linuxppc-2.6.9 Colin Wernham
2004-12-13 9:48 ` Mark Powell [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-12-10 9:09 Colin Wernham
2004-12-10 17:09 ` Matt Porter
2004-12-10 17:22 ` Stephen Williams
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